[GreenKeys] Loop currents

Roy Morgan k1lky68 at gmail.com
Sat Mar 3 13:59:04 EST 2018


Greenkey folks,

I recently got a W.E. 255A polar relay and located the Teletype Corporation Bulletin No. 120 Issue 7, March, 1944 that tells about it. 

The 255A is rated at signaling current of 60 Ma or 20 Ma (bias current half respectively).

From this we can assume these relays work well with holding magnets set for 20 Ma loop current. 

Roy sends.
> 
>   ...Model 14 and 15 with pulling magnet selectors have the magnets in series and operate at 60 ma.  Those with
> holding magnet selectors can be wired with magnets in series or parallel
> (some have a toggle switch) for 20 or 60 ma respectively.
> 
> ______________________________________________________________


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